This invention relates to thermographs and in particular those which are used in the storage and transport of perishables that are subject to critical temperatures ranging from chilled to frozen, it being a general object of this invention to provide an accurate and reliable electronic system for instant visual determination of adherence to requirements relating to time and temperature. Also, to provide documentation from stored data down-loaded from the thermograph and which is stored for subsequent readout or printout. In practice, a Liquid Crystal Display (LCD) is employed for instant visual Day-Hour time, and for High-Low temperature readouts, from an Electrical Erasable Programmable Read Only Memory (EEPROM). A personal Computer is employed for graphic and tabular readout and for printing hard copy documentation. Time and temperature data source is electronic and stored in the memory chip at selected time intervals for pre-programed trip durations. And, all of which is self contained in a battery powered unit.
It is the consignee of a shipment of perishables with which this invention is particularly concerned, and the trip-end information desired is selected by said consignee as may be required of the shipment involved. Accordingly, this is an electronic temperature recorder for use "In-Transit" or "On-Site" for monitoring perishables and temperature sensitive goods such as fresh fruits and vegetables, fresh or frozen meat, fish and poultry, processed foods, floral and nursery stock, seed, bulbs and fresh cut flowers, pharmaceuticals, blood, chemicals, film, resins, ink, leather, and any product that can be adversely affected by improper temperature. For example, asparagus is a commodity that must be transported within a narrow recommended temperature range of 32.degree.-35.degree. F./0.0.degree.-1.7.degree. C. and heretofore shippers have been known to refuse such shipments because of the inability to accurately operate within such temperature requirements. However, with the system concept herein disclosed the recipient or consignee is able to instantly extract and visibly examine exact information from the thermograph by viewing the LCD, using a simplified control panel, thereby eliminating the necessity of a strip-chart or conventional printout.
This electronic temperature recorder is not only provided for one-time "In-Transit" monitoring, but is also provided for repeated "On-Site" and "Fleet-Truck" monitoring; also for cold rooms, laboratories, freezers (walk-ins), restaurant facilities, retail outlet facilities, meat lockers etc. Generally, this electronic thermograph is adapted for use anywhere product safety and quality is dependant upon refrigeration and/or protection against heat and cold. It is therefore an object of this invention to provide data that can be instantly viewed by personel in charge of a facility, or mobile unit, and data that can be viewed at any time, printed and stored for future reference, all in accordance with Hazardous Analysis of Critical Control Points (HACCP) Government Requirements. A feature is the down-loading of time and temperature information into available computers, for example the widely used Personal Computers (PC's) with Windows by providing a driver-receiver means for converting instrument CMOS level information signals into PC level information signals to enable down-loading.
The stored information is retrievable in visual or printed form by the consignee at the end of a trip, or by the instrument source personel when the instrument is returned to said source; using state of the art Personal Computers (PC's) for viewing and for documentation. In practice, a pre-programmed diskette is included with each thermograph to operate a PC running Microsoft Windows, or the like.
The shipment of goods involves time periods varying from a day to a month or two, or more. Therefore, thermographs of the type under consideration are prepared to accommodate varied recording time periods, for example 5, 10, 20, 40 and 80 days; and corresponding chart formats are provided therefor. Heretofore, such instruments with or without strip-charts installed therein have been supplied to the shippers of goods in ready form to be started by the shipper when the transit period begins. Quite often however, the shipper fails to start the instrument in which case no recording is made during transit, it being an object of this invention to ensure a time and temperature recording regardless of whether the shipper started the instrument. This is accomplished by initiating operation of a default mode at the time of manufacture thereby putting the instrument in a permanent running condition. For example, a default time and temperature data recording mode is programmed for sampling temperature at 1 hour intervals, repeatedly going through the bit memory capability of the EEPROM during the shelf-life of the battery power supply.
In accordance with this invention, when the instrument is started to record a trip of pre-programed duration the default mode recording is preempted and the pre-programed trip recording mode is started to sample temperature at closely spaced time intervals for high resolution, for which this instrument is notably capable. For example, 15 minute sample intervals are pre-programmed in any one of the 5, 10, 20, 40, and 80 day chart modes. It is to be understood that the recipient of the instrument has the choice of a hard copy document in addition to an instant visible readout of the Liquid Crystal Display (LCD) of the instrument. And in the event that the shipper did not start the instrument, nevertheless there will be a full and complete time and temperature recording for a period up to 85 days (approx.) which is the memory capacity of the instrument using a 65568-bit EEPROM and based upon 15 or 60 minute intervals, for stored data at a high or a reduced resolution.
Documentation of time and temperature data is unnecessary, as the receiver of goods has the opportunity of inspection and acceptance without the instrument data. However, in the event of questionable temperatures, reliable documentation then becomes necessary in order to determine time and temperature conditions to which the goods were subjected in transit. Therefore, it is an object of this invention to provide down-loading means by which time and temperature data stored in the instrument is made compatable with a Personal Computer (PC) and from which hard copy documents can be made at any time after the trip period has ended. In the preferred form this documentation capability is implemented by an IBM personal computer running Microsoft Windows.RTM., and by providing a programmed diskette with each instrument, there being ports in the form of a standardized female nine pin RS232 connector on the instrument for down-loading it into a PC for screening and for printer readout of hard copy charts on standard sized paper.
The thermograph instrument as it is herein disclosed is characterized by its ROM based CMOS microcontroller that governs all functions not controlled by the shipper and receiver personel. In practice, a Read Only Memory ROM Based 8-Bit CMOS Microcontroller is employed to establish real clock time and to select time intervals for triggering sequential recordation of temperature samples associated with time, and for transmitting associated time and temperature output to and from a memory. The microcontroller is responsive to manual switches to begin and end recording, and including means to separately recall time and temperature sampled during the recording. Shipping is world wide, in which case In-Transit goods must pass from Time-Zone to Time-Zone. Therefore, it is an object of this invention to provide time zone correction means, whereby the consignee's real time is automatically displayed and documented. Accordingly, the aforesaid diskette that goes with the instrument contains software that programs the consignee's personal computer for correcting any variation in time difference between the shipper and the consignee.
The microcontroller chip is initialized at the time of deployment to the shipper for performing the aforesaid instrument operations, the power supply battery being permanently soldered into the instrument circuit at the time of manufacture for its continued operation.
A significant feature is that "HIGH" and "LOW" temperature data is instantly available at any time the LCD is open for observation, in either Farenheit or Celsius readings, this function being enabled by precluding both "pre-record" and "post-record" time periods from the LCD display, so that temperature saturation of the goods is complete whereby temperature response of the instrument is properly displayed and/or recorded only when goods temperature has been normalized.